U.S. patent number 6,029,309 [Application Number 08/831,252] was granted by the patent office on 2000-02-29 for vacuum cleaner with dust bag fill detector.
This patent grant is currently assigned to Yashima Electric Co., Ltd.. Invention is credited to Nobuo Imamura.
United States Patent |
6,029,309 |
Imamura |
February 29, 2000 |
Vacuum cleaner with dust bag fill detector
Abstract
A vacuum cleaner with an indicator for indicating when the dust
bag for the vacuum cleaner is full. The indicator includes a
turbine provided in a suction pipe, so that the turbine causes an
amount of electric power to be generated that corresponds to the
amount of negative pressure within the suction pipe. As the dust
bag begins to fill, the negative pressure in the suction pipe
decreases, and the amount of electric power caused by the turbine
also decreases. When the amount of electric power caused by the
turbine falls below a predetermined value, the indicator display
indicates that the bag is full. If the indicator is employed with a
dust sensor, the indicator display can be used to show the amount
of detected dust until the bag is full and the operation of the
sensor is stopped to allow the display to indicate that the bag is
full.
Inventors: |
Imamura; Nobuo (Kyoto,
JP) |
Assignee: |
Yashima Electric Co., Ltd.
(Kyoto, JP)
|
Family
ID: |
26145367 |
Appl.
No.: |
08/831,252 |
Filed: |
April 8, 1997 |
Current U.S.
Class: |
15/319;
15/339 |
Current CPC
Class: |
A47L
9/19 (20130101); B01D 46/0086 (20130101); B01D
46/02 (20130101); B01D 46/446 (20130101); B01D
2279/55 (20130101) |
Current International
Class: |
A47L
9/10 (20060101); A47L 9/19 (20060101); B01D
46/44 (20060101); B01D 46/02 (20060101); A47L
009/28 () |
Field of
Search: |
;15/319,339 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Moore; Chris K.
Attorney, Agent or Firm: Smith, Gambrell & Russell,
LLP
Claims
What is claimed is:
1. A vacuum cleaner comprising;
a vacuum cleaner body,
a suction pipe connected to the vacuum cleaner body, for guiding
dust and air to the vacuum cleaner body,
a fan motor provided within the vacuum cleaner body for generating
a suction force,
a dust bag for collecting dust suctioned by the suction force,
a generator, the generator being positioned along the suction pipe
such that the generator is driven by air suctioned through the
suction pipe to generate an amount of electric power corresponding
to an amount of negative pressure within the suction pipe,
a dust sensor for detecting dust suctioned by the suction force,
and
collected dust quantity indirect detection and display means for
producing a comparison result signal in response to the amount of
electric power generated by the generator being less than a
predetermined amount of electric power that stops operation of dust
sensor, and for indicating that the dust bag is full in response to
the comparison result signal and displaying detection results from
the dust sensor when the comparison result signal is not
produced.
2. A vacuum cleaner as set forth in claim 1, wherein the collected
dust quantity indirect detection and display means produces the
comparison result signal only after the amount of electric power
generated by the generator is continuously less than the
predetermined amount of electric power for more than a
predetermined amount of time.
3. A vacuum cleaner as set forth in claim 1, wherein the collected
dust quantity indirect detection and display means includes a
display light,
the display light is continuously active to display detection
results of the dust sensor, and
the display light intermittently activates to indicate that the
dust bag is full.
4. A dust bag fill detector for detecting when a dust bag of a
vacuum cleaner is full, comprising:
a generator for positioning along a suction path of a vacuum
cleaner, such that the generator will generate an amount of power
corresponding to a suction force of the vacuum cleaner;
collected dust quantity indirect detection means for producing a
comparison result signal in response to the amount of electric
power generated by the generator being less than a predetermined
amount;
a dust sensor for detecting dust suctioned by the suction force;
and
a display responsive to detection results from the dust sensor and
the comparison result signal from the collected dust quantity
indirect detection means, such that the display indicates that the
dust bag is full when the comparison result signal is produced, and
indicates the detection results from the dust sensor when the
comparison result signal is not produced.
5. A dust bag fill detector as set forth in claim 4, wherein the
collected dust quantity indirect detection means produces the
comparison result signal only after the amount of electric power
generated by the generator is continuously less than the
predetermined amount for more than a predetermined amount of
time.
6. A dust bag fill detector as set forth in claim 5, wherein
operation of the dust sensor is stopped when the comparison result
signal is produced.
7. A vacuum cleaner, comprising:
a vacuum cleaner body;
a suction pipe connected to the vacuum cleaner body, for guiding
dust and air to the vacuum cleaner body;
the dust bag fill detector as set forth in claim 6 positioned along
the suction pipe;
a fan motor provided within the vacuum cleaner body for generating
a suction force; and
a dust bag for collecting dust suctioned by the suction force.
8. A dust bag fill detector as set forth in claim 5, wherein
the display includes a display light,
the display light is continuously active to display detection
results of the dust sensor, and
the display light intermittently activates in response to the
comparison signal.
9. A dust bag fill detector as set forth in claim 8, wherein
operation of the dust sensor is stopped when the comparison result
signal is produced.
10. A vacuum cleaner, comprising:
a vacuum cleaner body;
a suction pipe connected to the vacuum cleaner body, for guiding
dust and air to the vacuum cleaner body;
the dust bag fill detector as set forth in claim 9 positioned along
the suction pipe;
a fan motor provided within the vacuum cleaner body for generating
a suction force; and
a dust bag for collecting dust suctioned by the suction force.
11. A vacuum cleaner, comprising:
a vacuum cleaner body;
a suction pipe connected to the vacuum cleaner body, for guiding
dust and air to the vacuum cleaner body;
the dust bag fill detector as set forth in claim 8 positioned along
the suction pipe;
a fan motor provided within the vacuum cleaner body for generating
a suction force; and
a dust bag for collecting dust suctioned by the suction force.
12. A vacuum cleaner, comprising:
a vacuum cleaner body;
a suction pipe connected to the vacuum cleaner body, for guiding
dust and air to the vacuum cleaner body;
the dust bag fill detector as set forth in claim 5 positioned along
the suction pipe;
a fan motor provided within the vacuum cleaner body for generating
a suction force; and
a dust bag for collecting dust suctioned by the suction force.
13. A dust bag fill detector as set forth in claim 4, wherein
operation of the dust sensor is stopped when the comparison result
signal is produced.
14. A vacuum cleaner, comprising:
a vacuum cleaner body;
a suction pipe connected to the vacuum cleaner body, for guiding
dust and air to the vacuum cleaner body;
the dust bag fill detector as set forth in claim 13 positioned
along the suction pipe;
a fan motor provided within the vacuum cleaner body for generating
a suction force; and
a dust bag for collecting dust suctioned by the suction force.
15. A dust bag fill detector as set forth in claim 4, wherein
the display includes a display light,
the display light is continuously active to display detection
results of the dust sensor, and
the display light intermittently activates in response to the
comparison signal.
16. A vacuum cleaner, comprising:
a vacuum cleaner body;
a suction pipe connected to the vacuum cleaner body, for guiding
dust and air to the vacuum cleaner body;
the dust bag fill detector as set forth in claim 15 positioned
along the suction pipe;
a fan motor provided within the vacuum cleaner body for generating
a suction force; and
a dust bag for collecting dust suctioned by the suction force.
17. A vacuum cleaner, comprising:
a vacuum cleaner body;
a suction pipe connected to the vacuum cleaner body, for guiding
dust and air to the vacuum cleaner body;
the dust bag fill detector as set forth in claim 4 positioned along
the suction pipe;
a fan motor provided within the vacuum cleaner body for generating
a suction force; and
a dust bag for collecting dust suctioned by the suction force.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum cleaner. More
particularly, the present invention relates to a vacuum cleaner
which detects when a dust bag is full with sucked dust.
In the past, an arrangement of a vacuum cleaner is popularly
employed that an air intake and an air outlet are provided whereby
a vacuum cleaner body, a dust bag and a fan motor are provided at
predetermined positions at an interior of the vacuum cleaner body.
Specifically, the fan motor is disposed with its outer periphery
surrounded by an airtight packing.
When the vacuum cleaner having the above arrangement is employed, a
suction force (negative pressure) is generated by the fan motor,
air including dust is sucked by the suction force through a suction
nozzle, a suction pipe and the air intake, and the dust is
collected by the dust bag while the air penetrates the air bag and
is exhausted through the air outlet to an exterior of the vacuum
cleaner body. Therefore, a quantity of dust collected by the dust
bag increases by performing a cleaning operation intermittently or
continuously for a long time period, and the dust bag approaches a
full condition with collected dust.
When the dust bag is filled with sucked dust, the dust bag is
blocked and the air penetration ability of the dust bag is lost.
Therefore, the suction force from the fan motor is not transmitted
to the air intake so that a condition is realized that air is
scarcely suctioned (and cleaning is scarcely performed).
Consequently, the collected dust within the dust bag should be
removed from the dust bag when such a condition is realized.
A mechanism (i.e., a dust quantity display mechanism) for detecting
a condition where the dust bag is filled with collected dust is
provided in a conventional vacuum cleaner. As shown in FIGS. 8 and
9, the mechanism includes a casing 41 having a rectangular
parallelepiped shape, a cylindrical shape or the like and a
communicating pipe 42 provided at a wall of the casing 41, which
wall is at one end in a longitudinal direction of the casing 41.
The communicating pipe 42 communicates an interior of the casing 41
and a space (the space rear of the dust bag) between the vacuum
cleaner body and the dust bag, as is illustrated in FIG. 8. A
display body 44 is housed within the casing 41 in a slidable manner
and a spring 45 is provided for urging the display body 44 in a
direction away from the communicating pipe 42. Further, a
transparent window 43 is provided at a predetermined position of a
wall which is parallel to the moving direction of the display body
44. The transparent window 43 is used to visually recognize a
position of the display body 44. A collected dust quantity display
(for example, showing empty, medium and full) 46 for indicating a
collected dust quantity is provided at a predetermined position of
the casing 41 adjacent to the window 43, as is illustrated in FIG.
9.
When this arrangement is employed, and when a quantity of dust
collected within the dust bag is nearly zero, a large quantity of
air is suctioned through the air intake by the fan motor which is
rotated at high speed, so that a negative pressure within the space
rear of the dust bag becomes extremely small. Therefore, the
display body 44 is moved by the spring 45 to display that a
quantity of dust collected within the dust bag is nearly zero
(refer to the display body 44 and the collected dust quantity
display 46 in FIG. 9).
On the contrary, when the dust bag is filled with suctioned dust, a
quantity of suctioned air through the air intake is almost zero
even when the fan motor rotates at extremely high speed, so that a
negative pressure within the space rear of the dust bag becomes
extremely great. Therefore, the display body 44 is moved against
the force of the spring 45 to display that the dust bag is filled
with suctioned dust.
Further, when the quantity of dust collected within the dust bag is
an intermediate quantity, the negative pressure within the space
rear of the dust bag varies in correspondence to the quantity of
collected dust. Therefore, the display body 44 is moved in
correspondence to the amount of negative pressure and the force of
the spring 45 so that a quantity of dust collected within the dust
bag is displayed.
The dust quantity display mechanism having the above arrangement is
a mechanism which is quite different from the cleaning function
which is the essential function of a vacuum cleaner. Therefore,
providing the dust quantity display mechanism is performed by
adding an extra mechanism to the vacuum cleaner. Consequently, a
disadvantage arises that a manufacturing cost of a vacuum cleaner
is increased.
Further, as is apparent from the above description, the dust
quantity display mechanism must be disposed in the vacuum cleaner
body. A disadvantage arises in that visually recognizing the dust
quantity display mechanism becomes inconvenient and a forced
condition for a cleaning operator. More particularly, a cleaning
operator actually performing a cleaning operation performs a
cleaning operation while looking at an operating section and the
like which is provided at the suction nozzle or the suction pipe.
And, during the cleaning operation, the vacuum cleaner body moves
in a pulled manner by the suction pipe. Therefore, when the dust
quantity display mechanism is to be visually recognized, an
operator must turn back to look at the vacuum cleaner body and into
the transparent window 43 having an extremely small size in
comparison to a size of the vacuum cleaner body. Consequently,
visually recognizing the dust quantity display mechanism is
inconvenient and a forced condition to a cleaning operator.
SUMMARY AND OBJECTS OF THE INVENTION
It is an object of the present invention to decrease the
manufacturing cost of a vacuum cleaner.
It is another object of the present invention to allow an operator
to visually recognize a dust quantity display mechanism without
giving inconvenience and a forced condition to a cleaning
operator.
A vacuum cleaner according to the present invention comprises a
vacuum cleaner body and a suction pipe connected to the vacuum
cleaner body, wherein the suction pipe guides dust with air to the
vacuum cleaner body and has an operation section at a predetermined
position thereof. The vacuum cleaner body includes therein a fan
motor for generating a suction force for suctioning dust and air,
and a dust bag for collecting the dust among the suctioned air and
dust. The operation section includes a generator and a control
section, the generator being driven by air suctioned by through the
operation section so that electric power is generated. The control
section includes a collected dust quantity detection and display
means, which compares the generated electric power and a
predetermined electric power so as to obtain a comparison result,
indirectly detects the quantity of dust within the dust bag based
upon the comparison result, and then displays the detection
result.
When the vacuum cleaner having the above arrangement is employed,
dust and air are guided to an interior of the vacuum cleaner body
through the suction pipe by operation of the fan motor. Therefore,
dust is collected within the dust bag and the generator is operated
so that electric power is generated.
When a quantity of dust within the dust bag is small, air smoothly
passes through the dust bag so that the quantity of air suctioned
by the suction force through the operation section is greater and
the amount of electric power generated by the generator becomes
greater. On the contrary, when the quantity of dust within the dust
bag is great, air does not smoothly pass through the dust bag so
that the quantity of air suctioned by the suction force through the
operation section is smaller and the amount of electric power
generated by the generator becomes smaller.
Therefore, the collected dust quantity indirect detection and
display means detects a quantity of dust within the dust bag based
upon the amount of electric power generated by the generator which
varies depending upon a quantity of dust within the dust bag, and
displays the detection result.
As is apparent from the foregoing, the collected dust quantity
indirect detection and display means detects and displays the
quantity of dust electrically. Thus, the limitation that the
display must be provided in the vacuum cleaner body, such as with a
conventional display mechanism, does not exist. Instead, the
display means according to the invention can be provided at a
desired position of the vacuum cleaner. Consequently, the
manufacturing cost of the vacuum cleaner is decreased, and the dust
quantity display can be visually recognized without giving
inconvenience and a forced condition to a cleaning operator.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a vacuum cleaner to which the present
invention is applied,
FIG. 2 is a schematic cross sectional view illustrating an interior
of a vacuum cleaner body,
FIG. 3 is a schematic cross sectional view illustrating an interior
of an operation section casing according to one embodiment of the
invention,
FIG. 4 is a block diagram illustrating an electric arrangement of a
dust quantity detection and display apparatus for indirectly
detecting a quantity of dust within a dust bag according to one
embodiment of the invention,
FIG. 5 is a diagram illustrating a relationship between a negative
pressure and an output current of a turbine generator,
FIG. 6 is a block diagram illustrating an electric arrangement of a
dust quantity indirect detection and display apparatus according to
another embodiment of the invention,
FIG. 7 is an electric circuitry diagram in correspondence to FIG.
6,
FIG. 8 is a cross sectional view illustrating a conventional dust
quantity display mechanism, and
FIG. 9 is a plan view of the conventional dust quantity display
mechanism shown in FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a schematic view of a vacuum cleaner to which the present
invention is applied, while FIG. 2 is a schematic cross sectional
view illustrating an interior of the vacuum cleaner body.
The vacuum cleaner includes a vacuum cleaner body 1 which has a
dust bag 2 and a fan motor 3 in an interior of the vacuum cleaner
body 1, a suction pipe 4 which is connected to the vacuum cleaner
body 1 in a removable manner, an extension pipe 5 which is
connected to the suction pipe 4 in a removable manner and a suction
nozzle 6 which is connected to a leading edge section of the
extension pipe 5 in a removable manner.
The vacuum cleaner body 1 has a first air intake 11 at one end and
an air outlet 12 at its other end. Within the vacuum cleaner body
1, the dust bag 2 is disposed at the first air intake side in a
removable manner and the fan motor 3, which is maintained with an
airtight packing 3a, is disposed on the air outlet side. A space
between the dust bag 2 and the fan motor 3 is a rear space 2a of
the dust bag.
The suction pipe 4 has an operation section casing 7 at a
predetermined position. The operation section casing 7 houses a
turbine generator 71 and a printed circuit board 72 as illustrated
in FIG. 3. The operation section casing 7 has a second air intake
73 for sucking in air which is used to drive the turbine generator
71. The suction pipe 4 has an air passage 74 for guiding air within
the suction pipe 4 which has already driven the turbine generator
71. Further, the operation section casing 7 has a light emitting
device 75 at a predetermined position. The turbine generator 71
supplies electric power for operation to electric circuitry mounted
on the printed circuit board 72, the light emitting device 75, and
the like.
FIG. 4 is a block diagram illustrating an electric arrangement of
an example of a dust quantity indirect detection and display
apparatus according to the invention for indirectly detecting a
quantity of dust within the dust bag.
In the dust quantity detection and display apparatus, an output
current of the turbine generator 71 is detected by an output
current detection section 81 so as to obtain a detection result.
The detection result then is supplied to a full display ON/OFF
section 83 by intervening time constant circuitry 82. An
oscillation section 84 is controlled by an output signal of the
full display ON/OFF section 83, and an oscillation output of the
oscillation section 84 is supplied to a driver section 85 so that
the light emitting device 75 is operated and a condition is
displayed that the dust bag 2 is filled with dust.
The output current detection section 81 detects whether or not the
output current of the turbine generator 71 is smaller than a
predetermined value. The time constant circuitry 82 includes one or
more condensers which are charged or discharged responding to a
detection result signal from the output current detection section
81. The full display ON/OFF section 83 is controlled by a voltage
between both terminals of one of the condensers. The full display
ON/OFF section 83 controls the oscillation section 84 based upon
its output signal.
An operation of the vacuum cleaner having the above arrangement is
as follows.
When the fan motor 3 is driven by the operation of a power switch
(not illustrated), dust is sucked with air to the dust bag 2
through the suction nozzle 6, the extension pipe 5, the suction
pipe 4 and the first air intake 11. The air passes through the dust
bag 2 so that the dust is collected by the dust bag 2. An interior
of the suction pipe 4 develops a negative pressure condition by the
above air flow, so that air is suctioned to the interior of the
suction pipe 4 through the second air intake 73 and the air passage
74. The turbine generator 71 is rotated by the suctioned air flow
so as to output a current in correspondence to its rotation speed.
The negative pressure and the output current have a relationship in
that the output current increases following an increase of the
negative pressure, as is illustrated in FIG. 5. Further, the
negative pressure increases following an increase of suction force
due to the fan motor 3.
When a quantity of dust within the dust bag 2 is small, the air
passing ability of the dust bag 2 is high, and the suction force in
the suction path comprising the suction nozzle 6, the extension
pipe 5, the suction pipe 4 and the first air intake 11 is great.
Therefore, the output current of the turbine generator 71 is
great.
When a quantity of dust within the dust bag 2 increases, the air
passing ability of the dust bag 2 is lowered, and the suction force
in the suction path comprising the suction nozzle 6, the extension
pipe 5, the suction pipe 4 and the first air intake 11 becomes
smaller. Therefore, the output current of the turbine generator 71
becomes smaller.
When the output current detection section 81 detects that the
output current of the turbine generator 71 becomes smaller than a
predetermined value, the quantity of dust within the dust bag 2 is
greater than a predetermined quantity. Therefore, one or more
condensers of the time constant circuitry 82 are charged or
discharged responding to the detection result signal of the output
current detection section 81, and the full display ON/OFF section
83 is controlled by the voltage between both terminals of one of
the condensers. The full display ON/OFF section 83 operates the
oscillation section 84 by its output signal, which then operates
the light emitting device 75 by the intervening driver section 85
so that the light emitting device 75 indicates that the dust bag 2
is full with dust. The light emitting device 75 is provided at the
operation section casing 7, so that a cleaning operator can
visually recognize that the dust bag 2 is full with dust with a
posture which is a normal posture for performing a cleaning
operation without giving inconvenience and a forced condition such
as looking back to the vacuum cleaner. Of course, the dust quantity
indirect detection and display apparatus does not require a
complicated mechanical construction like a conventional dust
quantity display mechanism, so that a cost of the dust quantity
indirect detection and display apparatus is decreased and a
manufacturing cost of a vacuum cleaner is decreased.
Therefore, a disadvantage is prevented from occurrence that a
cleaning operation is continuously performed even when the dust bag
2 is full with dust and little suction force is realized.
FIG. 6 is a block diagram illustrating an electric arrangement of
another embodiment of a dust quantity indirect detection and
display apparatus.
This dust quantity detection and display apparatus differs from the
above dust quantity indirect detection and display apparatus in
that a dust sensor 91, comprising a light emitting device and a
light receiving device, is further provided, the light emitting
device 75 being driven based upon a detection result of the dust
sensor 91. A dust sensor stopping section 92 also is further
provided, which operates based upon the output signal of the full
display ON/OFF section 83 and stops a dust detection operation of
the dust sensor 91.
FIG. 7 is an electric circuitry diagram corresponding to the block
diagram of FIG. 6. However, an arrangement section corresponding to
the dust sensor 91 is not illustrated in FIG. 7.
In the output current detection section 81, a zener diode ZD1 and a
pair of forward diodes D1 and D2 are connected in series between
output terminals of the turbine generator 71. A resistor R1 is
connected in parallel to the pair of forward diodes D1 and D2.
Further, a connection point of the zener diode ZD1 and the diode D1
is determined to be a ground GND of the dust sensor 91.
In the time constant circuitry 82, a resistor R3 and
collector-emitter terminals of a transistor Q1 are connected in
series between the output terminals of the turbine generator 71. A
resistor R2 is connected between the base terminal of the
transistor Q1 and the connection point of the zener diode ZD1 and
the diode D1. A condenser C1 is connected between the base terminal
and the emitter terminal of the transistor Q1. A resistor R4 and a
condenser C2 are connected in series between the collector terminal
and the emitter terminal of the transistor Q1.
In the full display ON/OFF section 83, resistors R6 and R5 and
collector-emitter terminals of a transistor Q2 are connected in
series between the output terminals of the turbine generator 71. An
emitter terminal of a transistor Q4 is connected to the ground GND
of the dust sensor 91. A diode D3 is forward-connected between a
connection point of the resistor R4 and the condenser C2 and the
base terminal of the transistor Q2. A diode D4 is reverse-connected
between the connection point of the resistors R6 and R5 and the
ground GND of the dust sensor 91. A resistor R8 is connected
between the base terminal of the transistor Q4 and the connection
point of the resistors R6 and R5. A resistor R10 is connected
between the collector terminal of the transistor Q4 and the
positive output terminal of the turbine generator 71.
In the oscillation section 84, a resistor R11 and collector-emitter
terminals of a transistor Q5 are connected in series between the
positive output terminal of the turbine generator 71 and the ground
GND of the dust sensor 91. A resistor R13 and collector-emitter
terminals of a transistor Q6 are connected in series between the
positive output terminal of the turbine generator 71 and the ground
GND of the dust sensor 91. A base terminal of the transistor Q5 is
connected to the collector terminal of the transistor Q4. A
condenser C4 is connected between the base terminal of the
transistor Q5 and the collector terminal of the transistor Q6. A
condenser C3 is connected between the base terminal of the
transistor Q6 and the collector terminal of the transistor Q5. A
resistor R12 is connected between the positive output terminal of
the turbine generator 71 and the base terminal of the transistor
Q6.
In the driver section 85, the emitter terminal of a transistor Q7
is connected to the ground GND of the dust sensor 91. A base
terminal of the transistor Q7 is connected to the collector
terminal of the transistor Q6 by an intervening resistor R14. The
collector terminal of the transistor Q7 is connected to a cathode
of the light emitting device 75 included within the dust sensor 91
by an intervening resistor R15.
In the dust sensor stopping section 92, the emitter terminal of a
transistor Q3 is connected to the ground GND of the dust sensor 91.
A base terminal of the transistor Q3 is connected to the collector
terminal of the transistor Q2 by an intervening resistor R7. The
collector terminal of the transistor Q3 is connected to the
positive output terminal of the turbine generator 71 by an
intervening resistor R9. The emitter terminal of a transistor Q8 is
connected to the ground GND of the dust sensor 91. The base
terminal of the transistor Q8 is connected to the collector
terminal of the transistor Q3, while the collector terminal of the
transistor Q8 is connected to a positive input terminal of an
operational amplifier (not illustrated) included within the dust
sensor 91.
The operation of the dust quantity indirect detection and display
apparatus having the above arrangement is as follows.
When the fan motor 3 is driven by operation of a power switch (not
illustrated), dust and air are suctioned to the dust bag 2 through
the suction nozzle 6, the extension pipe 5, the suction pipe 4 and
the first air intake 11. The air passes through the dust bag 2 so
that the dust is collected by the dust bag 2. An interior of the
suction pipe 4 develops a negative pressure condition by the above
air flow, so that air is suctioned to the interior of the suction
pipe 4 through the second air intake 73 and the air passage 74. The
turbine generator 71 is rotated by the suctioned air flow so as to
output a current corresponding to its rotation speed. The negative
pressure and the output current have a relationship in that the
output current increases following an increase of the negative
pressure, as is illustrated in FIG. 5. Further, the negative
pressure increases following an increase of suction force due to
the fan motor 3.
When a quantity of dust within the dust bag 2 is small, an air
passing ability of the dust bag 2 is high, and a suction force of
the suction path comprising the suction nozzle 6, the extension
pipe 5, the suction pipe 4 and the first air intake 11 is great.
Therefore, the output current of the turbine generator 71 is
great.
In this case, a voltage between both terminals of the resistor R1
of the output current detection section 81 increases when the
output current becomes great. When the voltage between both
terminals of the resistor R1 reaches a first predetermined voltage
(for example, about 0.6 volts), the transistor Q1 turns on so that
the condenser C2 is discharged. As a result, the transistor Q2
turns off so that the transistors Q3 and Q4 turn on. The transistor
Q8 turns off as a result of the transistor Q3 being turned on, so
that the dust sensor 91 operates. The dust sensor 91 detects a
quantity of dust included within suctioned air suctioned through
the suction nozzle 6, the extension pipe 5, the suction pipe 4 and
the first air intake 11. The dust sensor 91 drives the light
emitting device 75 so as to visually display the quantity of
dust.
During the above operation being performed, the transistor Q4 is
turned on so that the oscillation section 84 does not operate.
Therefore, the light emitting device 75 is not influenced by the
above operation at all.
When a quantity of dust within the dust bag 2 is increased by
performing a cleaning operation, the air passing ability of the
dust bag 2 is lowered so that the suction force through the suction
path comprising the suction nozzle 6, the extension pipe 5, the
suction pipe 4 and the first air intake 11 and the output current
of the turbine generator 71 becomes smaller.
Even when cleaning is performed, the above operation is performed
when the voltage between both terminals of the resistor R1 reaches
the first predetermined voltage.
On the contrary, when the voltage between both terminals of the
resistor R1 does not reach the first predetermined voltage, the
transistor Q1 is maintained to be off so that the condenser C2 is
charged. When a voltage between both terminals of the condenser C2
reaches a second predetermined voltage (for example, about 1.2
volts), the transistor Q2 turns on so that the transistors Q3 and
Q4 turn off. When the transistor Q3 turns off, the transistor Q8
turns on so that the dust sensor 91 stops its operation.
Further, when the transistor Q4 turns off, the condenser C4 is
charged. When a voltage of the base terminal of the transistor Q5
reaches a third predetermined voltage (for example, about 0.6
volts), the transistor Q5 turns on and the transistor Q6 turns off.
Under this condition, the condenser C3 is charged. When a voltage
of the base terminal of the transistor Q6 reaches the third
predetermined voltage, the transistor Q6 turns on and the
transistor Q5 turns off. Thereafter, charging of the condenser C4,
charging of the condenser C3 and turning on and turning off of the
transistors Q5 and Q6 in correspondence to the charging are
repetitively performed so that the oscillation section 84 outputs a
signal which varies its level periodically. During the transistor
Q6 being turned off, the transistor Q7 turns on so that the light
emitting device 75 is driven. Therefore, a display indicating the
dust bag 2 being full with dust is performed.
Consequently, a disadvantage is prevented from occurring where a
cleaning operation is continued even when the dust bag 2 is full
with dust and when little suction force is realized.
Further, the dust quantity indirect detection and display apparatus
employs the time constant circuitry 82. Therefore, even when the
output current of the turbine generator 71 momentarily reaches a
value which represents the dust bag 2 being full with dust, and
when the output current does not continue for a time to some
degree, a display indicating the dust bag 2 being full with dust is
not performed so that a mis-operation is securely prevented from
occurring.
As is apparent from the foregoing description, the dust quantity
indirect detection and display apparatus does not require a
complicated mechanical arrangement such as a conventional dust
quantity display mechanism, and the light emitting device 75 is
used both for displaying when the dust bag 2 is full with dust and
displaying a quantity of suctioned dust. Therefore, a further
decrease in cost of the dust quantity indirect detection and
display apparatus is realized and a manufacturing cost of a vacuum
cleaner is decreased.
* * * * *